| 摘要 |
<P>PROBLEM TO BE SOLVED: To highly accurately diagnose sensitivity abnormality of a cylinder pressure sensor. Ž<P>SOLUTION: In this abnormality diagnostic device, a total heat production parameter ΔPV<SP>κ</SP>correlating with the total heat production generated by one combustion of an internal combustion engine is normalized by a fuel amount τ to calculate a combustion parameter H corresponding to a low heat production q<SB>fuel</SB>of the fuel, and an abnormality in the cylinder pressure sensor is diagnosed based on the combustion parameter H and the low heat production q<SB>fuel</SB>. The expression of ΔPV<SP>κ</SP>=P(θ<SB>2</SB>)V(θ<SB>2</SB>)<SP>κ</SP>-P(θ<SB>1</SB>)V(θ<SB>1</SB>)<SP>κ</SP>is satisfied, wherein the P(θ<SB>1</SB>) and P(θ<SB>2</SB>) are cylinder pressure detected by the cylinder pressure sensor at predetermined crank angles of θ<SB>1</SB>, θ<SB>2</SB>before and after the combustion, the V(θ<SB>1</SB>) and V(θ<SB>2</SB>) are cylinder capacities at the crank angles θ<SB>1</SB>, θ<SB>2</SB>, and the κ is a predetermined ratio of specific heat. When the sensitivity of the cylinder pressure sensor is abnormal, the sensitivity abnormality of the cylinder pressure sensor is diagnosed, by using a fact that a value of a combustion parameter H is not approximately equal to a value of the low heat production q<SB>fuel</SB>. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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